<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>后盾人</title>
  </head>
  <body>
    <button onclick="this.hide()">后盾人</button>
  </body>
  <script>
    Object.prototype.hide = function() {
      this.style.display = "none";
    };
  </script>
  <script src="20.js"></script>
</html>
